Magnetic-chuck.



L. W. DOWNE-s.

MAGNETIC oHucx.

- APPLICATION FILED JULY 21,193.0, 1,036,976. Patented Aug. 27, 1912.

3 SHEETS-SHEET 1l L. W. DOWNES.

MAGNETIC CHUCK.

APPLICATION FILED JULY 21,1910.

1,036,976, Patented Aug. 27, 1912.

3 SHEETS-SHEET 2.

L. W BOWNES.

MAGNETIC CHUCK.

APPLIOAToN FILED JULY21,1910.

3 SHEETS-SHEET 3.

Patented Aug. 27, 1912.

LQUIST W.' DOWNES; -OF BROVIDENCE, RHODE ISLAND;

MAGNETIC CHUCK.

To @ZZ whom tmcy @0f/wem:

Be it known that I, Louis W. DowNns,

y of Providence, Rhode Island, have invented out a new and. usefulA Improvement in Magnetic Chucks, which invention is fully set forthy in the following specication.

This invention relates to magnetic chucks tor. holding magnetic material in position while being subjected to machining operations, and hasfor its object to provide a device of this kind, which is simple in constrnctiomcapable of developing a plurality ot powerful magnetic fields, and'is provided with magnetic coils whichlmayv be immediately replaced by stock coils of standard sizes-in case any one of them is injured by burningoout or disabled by accident.

Magnetic chucks as heretofore constructed pre-sent the serious defect when the 'ting coil.` is accidentally burned out or otherwise disabled of requiring the devicev be returned to the factory for renewal of its coil, because the 'chuck' is so assembled that thewinding can not be replaced with great difficulty and loss of much time. My invention overcomes the above objections and secures-the objects named by providing a magnetic chuck with a plurality of interchangeable magnetizing coils, each oit a simple bobbin round-shape or ring form, and. ofafstandard size wherebyv a. new coil from stock may be quickly substituted in the chuck' for one burned out or otherwise needing renewal. I preferably. construct the chuclrwith abase or supporting plate of caste or. wrought-iron, toy which iron cores are made fast, the tree ends of which form pole-pieces distributed in the tacco-1t" the chuck. The corresponding` poles are formed in a. body member of' iron having perorations coaxial with the magnet cores, each perforation forming an annular space around eachcore. In this annular space, and over each core, I slip an exciting coil made preferably of deltabeston wound wire, and secured in place byaclamping or other fasteningv means. These coils are of standard sizes as to dimensions, and size ci" wire for accommodating different kinds of chucks. The coils may bc connected in series or parallel. Each coil may be renoved without disturbingA the others, or all the coils may be readily removed with very l tie loss of by removal of' the body the chuck from its base plata l'ly improvement is equally applicable to magnetic chucks designed for holding work to a movable or stationary bed plate or to chucks to be mounted on. lathes. The electric connections between the coils are preferably made through channels in the body of the chuck. Connections to the source of current are made through terminal blocks or, in the case of a revoluble chuck, through slip rings.

The inventive idea may' assume a varietyA of mechanical expressions, some of which are illustratedin the accompanying drawings which are designed merely for the purposes of illustration and not as limiting the invention, reference beingy had to the claims for this purpose.

In the drawings z-Figure ly /is a plan view, with certain parts removed, showing a magnetic chuck embodying my improvements; Fig. 2 is a view of the same in longitudinal, ccntral, vertical section, on thel linel 2;-2 oi' Fig. 1"; Fig. 3 is an end view inl elevation 'of 'the magnetic chuck shown in Figs.. l' andifZ; Fig. 4lisa dia.- graimnatic` planview showing the application of'my improvements to` larger chucks; Fig. 5"v is a diagram showing connections with an electric supply circuit; F ig. 6 is a side elevational view with parts broken away, showingmy improvements applied to' rcvoluble chuck, and Fig. 7. is an end elevationall view otthechuckshown in Fig. 6 the parts beingV removed to show the interior construction.

Referring more particularly to Figs. l, 21 and 3, I have herein illustrated a4 triple `iield magnetic chuckin which l is the baseplate preferably made of cast-irom rectangular in shape and machined up, and provided with'three openings or sockets 2 shown as round in the drawings, though any other form of opening may be employed. The base-plate l is provided with means, such as slotted" brackets 3, 3, for securing it to the bed of a milling machine or other object, and with conductor receiving grooves 5, 6. lifountedl on base plate l, and secured thereto by screws or other means not shown, is an iron pole or plate 7 of either wrouglitor cast-iron, having openings 8, the number oi"v which corresponds with the openings 2 in the plate l'. These openings are preferably circular, and are larger than openings 2, but coaxial therewith, and are enlarged somewhat at their upper ends to form annular ledges 9'in the sol body of the pole-piece. lnto openings 2 in the bed-plate 1 are forced pole-pieces 10, two only being shown in Fig. 2. Each polepiece 10 is preferably machined down from round wrought-iron stock into a cylindrical form having a body portion somewhat larger than the opening 2, and a lower reduced portion 11 adapted to fit snugly in said opening. rlhe opposite or upper end of the core 10 is provided with a shoulder 12, which with the opposite ledge 9 in poleplate 7, is adapted to support a. coil retaining or sealing ring 13 of a non-magnetic metal, such as brass, which may be secured in place by screws 14. ln one end of the frame member 7 l provide a recess or chainbcr for receiving a terminal block 15 of any preferred form, and of refractory material, such as porcelain or hard rubber, and secure the same to the wall or body of the frame by screws 16. r1`o this block connections are made both from the energizing coils through the channels 5, 6, in the base-plate 1, and from which leads a power circuit, as shown for example in Fig. 5. l preferably bring the leads of the powery circuit through side openings 17 in the pole-plate 7 and provide insulating linings 18 therein, which are secured in place by fastening means, such as screws 19. The face of the chuck is provided with means for preventing lateral slipping or displacement of the work which in this class of devices is held down by a force substantially normal to the surface, less resistance being oered by the work to forces acting in directions at right-angles thereto. comes desirable to take an unusually heavy out from the work, it may be necessary to provide additional means to prevent lateral displacement. To this end, l may provide the face of the clutch with abutment means, such as retaining studs 20 either fast thereto or removable therefrom and distributed at short intervals. rlhe face of the chuck will thus present a flat surface in which lie the ends of the magnet cores, the faces of the non-magnetic rings and the face of the poleplate together with the studs or holding rim. 'llhe magnetic chuck as thus constructed is provided with a plurality of annular chambers or coil spaces around the magnet c ores adapted to receive removable energizing coils. 1 propose to make these coils of different designs to fit chucks of different capacities, and thereby enable users of these chucks to quickly and readily replace an Iinjured coil by a new one kept in stock, or

readily procurable'without necessitating the return of the chuck to the factory for re-' pairs, or requiring the core to be removed, an operation which consumes time and requires the exercise of-skill and possession of means not always present at the place where the chucks are used,l

ln certain instances where it be rossore l preferably wind the coils on bobbins in form of rings with deltabeston wire and cover the ring with heateresisting and moisture-proof material, such as Deltasheeting, which is an asbestos paper treated with a composition suitable for rendering the paper impervious to moist-ure while capable of withstanding any temperature to which the coil is likely to be subjected in practice. The windings of the energizing coil are not only thus protected against moisture by a heat resisting and impervious covering, but are secured together by a wrapping so that each coil may be handled independently of a supporting spool and without disturbing the windings of the coil. While I prefer to make my coil in this manner, l do not desire to limit myself to this particular form, but may employ coils made in any other way, provided they have their windings bound or secured together and have the capability of being slipped in and 'out of the core spaces of the chuck to replace those injured. In Fig. 2*'lf`ha-ve sho-wn one such coil 21, provided with a covering 22. The coil is made of an eX# ternal diameter to readily slip into the coil space 8 in the pole plate 7, and has an opening adapted to receive the core-piece 10. rthe ends of this particular coil enter the channel 5 and connect through them with other coils and with the terminal block 15. rl`he several energizing coils may be connected in multiple, in series, or multiple series, according to the requirements of the service, and each coil within the coil space i1, retained therein by the closure or rings 13, which are made fast to the frame 7 by means of screws 14.

`While the coils may be inserted in the chuck in various ways, the following manner of replacing them is preferred: Assuming that one or more of the coils has been accidentally burned out, the base plate 1 is first disconnected from the frame 7. yThe magnet cores 10 which are fast to plate 1 are thereby slipped from their coils leaving the latter exposed together with their connections which previously rested in grooves 5 and t3. Any one of the coils can now be readily disconnected from the set and can -be replaced by a newfone kept in reserve,

and connected up in its place. The baseplate is then returned to its place with its cores threading the coils and its grooves over the connecting conductors. rfhis operation takes but a moment, and can be performed by a workman unskilled in electrical matters.

From the above description of the device the operation will be readily understood.

By means of slotted bracket-arms 3 the chuck is made fast to the bed of a milling or grinding machine in the usual way. rlhe work to be machined rests on the face of the chuck and may be wedged against lateral displacement between studs 20.4 The terminals of the block l5 are connected by flexible cord conductors to a power circuit preferablythrough an incandescent lamp resistance in series with the energizing coils as diagrammatically indicated in Fig. 5. Several advantages are hereby gained; the lampv pole-plate 7, some of the lines oil which areL indicated in F ig. 2. The work to be machined is placed on the face of the chuck in the path of the magnetic'lines which are hereby short-circuited and firmly draw the ivorl down and hold it tirinly on the chuck ace.

Should an excessive current pass through g the chuck and burn out one or more coils,

such coils may readily bereplaced-without delay'by slipping the injured coil oli its core in the manner above described, substituting a new one kept on hand for the purpose.

ln' Fig. l l have illustrated a similar chuck to that above described, except that the face of the chuclr presents a more eX- eiided surface and is provided with a larger number of energizing coils which/ find may made smaller while securing the desired rorce to hold the worlr against the tace. Economy is also edected when itbecomes necessary to replace injured coils.

lli Figs. 6 and 7 I have shown my im roveinent applied to a rotary magnetic -huclr in which the base-plate l is cylindrical land is provided with a shank 23 on which is mounted a commut-ator comprising insulating ring 23 with two met-al slip ri ge 25, 26, held out of contact with each other a portion of the insulating material or ring 23. The slip rings are provided terminals 27, 28, for electrically consaid necting the rings through insulated conductors 29, 30, running from the magnet coils through channels 31. The coils are of the same construction and are arranged inthe same manner with respect to their coresas previously described.` This form of magnetic clutch, while retaining the multiple magnetic field, simplicity of construction and the feature of removable coils, enables the work to be rotated, and is particularly useful in grinding such light articles as pisw ton-rings' which require rot-ation while uff-f dergoing such operation.

ll. A multiple field magnetic chuck coin- 'prising a magnetic pole platehaving a plurality of magnet coil receiving spaces the body of said plate forming a part of the magnetic path, magnet coils for saidspaces y and adapted to be slipped in and outof the samemagnet cores for said coils, and

magnet core holding plate detachably secured to one face of said pole blate. f

2. 'A multiple field magnetic chuck com v prising a magnetic pole plate having a plurality of magnet coil receiving spaces the body of said plate forming a part of magnetic path, magnet coils for said spaces and adapted to be slipped in and out of the same, magnet cores for said coils, a magnet core holding plate det-acliably secured to one face of said pole plate, and non-magnetic annular` plates for retaining said coils :T1

multiple ield magnetic chuck, com 4 prising a magnetic pole plate.` having .a pluiality of magnet coil receiving spaces the body ot' said plate forininga part of the magnetic path, magnet coils for said spaces and adapted to be slipped in and out of same, magnet cores for said coils, a magnet core holding plate detachably secured to one face of said pole plate and provided withy channels for ieceivingcoil connections2 and non-magnetic annular plates for retaining said coils in said spaces. y

ln testimony whereof I have signed this specification in the presence of two subscrib ing witnesses.

L'UIS W. DOVVNES.

Witnesses:

GEORGE W. STEERE E. L. SMITH. 

